Encapsulate semaphore handling

1 files changed, 59 insertions, 0 deletions

diff --git a/src/sem.h b/src/sem.h
new file mode 100644
index 0000000..f0b7183
--- /dev/null
+++ b/src/sem.h
@@ -0,0 +1,59 @@
+/*
+  Copyright (c) 2012-2014, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/**
+   \file
+
+   Portable semapores
+*/
+
+
+#pragma once
+
+#include "log.h"
+
+#include <semaphore.h>
+
+
+/** Generic semaphore type */
+typedef sem_t fastd_sem_t;
+
+
+/** Initializes a semaphore with a given value */
+static inline void fastd_sem_init(fastd_sem_t *sem, unsigned value) {
+	if (sem_init(sem, 0, value))
+		exit_errno("sem_init");
+}
+
+/** Increments the semaphore */
+static inline void fastd_sem_post(fastd_sem_t *sem) {
+	if (sem_post(sem))
+		exit_errno("sem_post");
+}
+
+/** Tries to decrement the semaphore */
+static inline bool fastd_sem_trywait(fastd_sem_t *sem) {
+	return !sem_trywait(sem);
+}